Tonometer



Jan. 2, 1945.

u. OLLENDORFF TONOMETER Filed March 21 '1944 Y UNITED STATE partly in section.

shown in Fig.1 1.

Patented Jan. 2, 1945 s PATENT OFFICE .TONOMETER' Ulrich oilendprrr, N wYmnN. Y.

. ppeasement 2 1, 1944;'SerialNo'. 527,452

, p 12 claims. This invention is a novel improvement in to nome'ters for measuring the tension of eyeballs, i.- 6., their softness or hardness, and the principal object oftheinvention is to provide a tonometer adapted to be used preferably, but not necese sarily, in a horizontal position on a' patient, in a sitting position as distinguished from tonometers heretofore used in whiehthe instrument di osed enlyonhisback; i t q Another object of the invention is to provide atonometer havingla novel arrangement ofecounterbalance weights and-levers, one being applied tobalance the pointer, and another being applied to regulate therpressureof force in applying the instrument to the eyeball at the moment of readvertically could be used on a patient when lying ing or measurement, the provision of the weights.

and. levers replacing what in former vertical measuring tonometers was effected by gravity.

I will explain the invention with reference to the accompanying drawing which illustrates onei the positionshown in Fig.1; and when the lever m is not subjected to a force other than gravity.

Slidably mounted withinthe' bore ofsleeve 5 is a pin l3 having a slightly enlarged head I3a' at its outer end within the frame or yoke 3 adapted to contact the arm "la of pointer 8, the pivot 1 of the pointer 8 being offset from the axis of pin I3 as hereinbefore stated; The bluntedinner endof pin I3 extends beyond the inner end of sleeve 5, as at 13b, and the adjacent end of sleeve 5 is provided with a disk-like enlargement 5b having a concave face 50' adapted "to receive and conform with the shape ofbthe' eyeball of the patient. Y in On the underside of sleeve .5disposed. intermediatethe collar 4 and. enlargement 5b isa key. ,5a, and slidably mounted uponthesleeve 5 between the inner end of key 5a and the collar 4 is s'lidably mounted a bushing l2-having=a keypractical embodiment thereof to enablefothers familiar with the art to adopt and use thesame; and will summarize in the claims, the novelfeatures of construction, and novelcombinations of parts for which protection is desired.

In said drawing- 4 i H i Fig. 1 is a frontelevation of the tonometer,

axis of sleeve 5 being disposed axially of plate I.

On plate II adjacent yoke 3 but ofiset above way I 2a therein, as shownin Figs. land 3, which keyway I2ais deeper at the inner) end of the bushing than at the outer end, the, bottom ,of

, keyway in being thusslightly tapered as shown.

Attached to the outer end. of bushing 12; are handles 12b adapted to be held by the operators hand to support the instrument and at thesametime to provide means for the sliding of the bushing l2 onsleeve5. g i i In order to .controlthe pressure at which the; instrument is applied to the eyeball, I provide an inwardly and downwardly inclined lever-.14

pivoted, as at Ma, to the inner end of key 5:: of

' the sleeve, said lever having a flattened face or the axis of sleeve 5 is a bearing lb (preferably antifriction) fora pivot, 1 carrying a pointer 8 secured thereto as at 9, said pointer 8 cooperating with scale 2'. Pivot 1 also carries a depending am; la orossingthe axis ofsleeve 5,,as shown, I

said arm 1a having at its lower end a downwardly andoutWardIy inclined counterbalancing lever H) which is threaded and which carries an adjustabie weight I"! p which may be adjusted orshiftedthereon to cause the pointer to gravitationally dverue a fixed point 2x or graduation of scale 2, or to gravitationally assumeany' other position, when the tonor'neter is held horizontally, 1. e, in

portion Mb adjacent the pivot I 4a engaging the underside of sleeve 5 to gravitationally maintain the lever I4 at an angle of about 30 to the, axis of sleeve 5 as shown in Fig. 1. Lever His threaded and carries an adjustable weight 15 which as shown more particularly in Fig. 4 has an arcuate recess [5a in its periphery adapted to conform;

with the curvature of'theunderside of; sleeve 5, and which will permit the lever M to be swung upwardly when engaged by theinner end of bushing 12. On lever I4 is a' mark 14:1: for the purpose hereinafter described. i

In operation, before using the tonometer, the

same is placed against a convex metallic test piece T shown'in dotted lines in Fig. 1,,which piece T conforms with the shape of the concave face 50 of the disk-like enlargement 5b, andthe weight ll adjusted so that the pointer indicates 3. The tonometer in the preferred use thereof 0. Normal eye pressure then will permit the pointer when in actual use to shift'into position is then held ihia horizontal position wltn the concave face 50 of the disk-llkeenlargement 5b just touching the anaesthesized eyeball of the patient with eyelids spread apart and when the patient is in a sitting position, and with the sleeve I2 out of contact with the'lever I4. At the.

moment of contact the pin I3 will start to move outwardly according to the intraocular pressure of the eyeball, the movement of pin I3 being directly transmitted to lever Ia which operates the pointer 8 and the pointer 8 will then start to rise on the scale 2. The balance of the pointer 8 will be effected by the weight I I on the inclined lever l carried by arm Ia, and if desired the weight thereon may be increased by placing additional weights II on lever II] or by mere adjustment of the single weight II along said lever. The bushing I2 will then be moved inwardly on sleeve 5 by shifting handles I2b in the direction of the eye of the patient, which movement will tend to likewise move the enlargement 51). into firmer contact with the eyeball due to'friction between the parts I2 and 5. Such movement of bushing I2 will cause the inner slotted end of bushing I2 opposite keyway I2a to contact the inclined lever I4 swinging same upwardly until the inner end of the bushing comes to the marked point I411: on the lever I4. At this moment the reading of the pointer 8 on scale 2 is taken giving the desired measurement of intra-ocular pressure. If the pointer 8 at the time-of reading is at position 0, the eyeball will be denoted as being very hard or subjected to undue intra-ocular pressure. The further the pointer swings away from 0 the softer is the eyeballs or the less the pressure. The tonometer however may if desired be applied in a vertical position to the eye of a patient While reclining on his back, in which case the lever I l will be subjected to gravity so that the weight I5 will touch sleeve 5. This however presents no infiuence upon the measurement.

I do not limit my invention to the exact form shown in the drawing, for obviously changes may be made therein within the scope of the claims.

I claim:

1. A tonometer, comprising a plate having a scale; a' pointer pivoted thereon and swingable.

over said scale; an arm on said pointer; a sleeve on said plate having a concave outer end shaped to the curvature of an eyeball; a pin slidable in said sleeve and having its inner end engaging said arm; the outer end of the pin normally projecting into said concave end of the sleeve; and means for adjusting the'balance of the pointer when the plate is held in. operative position.

2.. In a tonometer as set forth in claim 1, said adjusting means comprising a lever on the said arm inclined in the direction of the pointer; and a shiftable weight on said lever.

3. A tonometer, comprising a plate having a scale; a pointer pivoted thereon and swingable over said scale; an arm on said pointer; a sleeve on said plate having a concave outer end shaped to the curvature of an eyeball; a pin slidable in said sleeve and having itsinner end engaging said arm, the outer end of the pin normally projecting into said concave end of the sleeve; a bushing slidable on said sleeve; handles carried by said bushing whereby the tonometer may be supported and the bushing may be shifted towards the concave end of the sleeve; and means for controlling the force applied to the bushing in shifting the same during measurement.

4. In a tonometer as set forth in claim 3, said controlling means comprising a key on said sleeve engaging a keyway in said bushing; a lever pivoted at the end of the key adjacent the concave end of the sleeve; means gravitationally maintainingthe lever at an acute angle to the sleeve when the plate is in operative position; an adjustable Weight on said lever; and said lever having an indicia thereon cooperating with the adjacent end of the bushing to denote the proper position of the bushing on the sleeveduring its movement towards the concave end .of the sleeve when'the reading of the pointer on the scale should be taken.

5. In a tonometer as set forth in claim 3, said controlling means comprising a key on said sleeve engaging. a keyway in said bushing, a lever pivoted at the end of the key adjacent the concave end of the sleeve; means gravitationally maintaining the lever at an acute angle to the sleeve when the plate is in operative position; an adjustable weight on said lever having a recess in its periphery conforming with the shape of the sleeve to permit the lever to swing towards the:

sleeve when the bushing slidably contacts the lever; and said lever having an indicia thereon cooperating with the adjacent end of the bushing to denote the proper position of thebushing on.

the sleeve during its movement towards the concave end of the sleeve when the reading of the pointer on the scale should be taken.

6. A tonometer, comprising a plate having a scale; a pointer pivoted thereon and swingable over said scale; an-arm on said pointer; a sleeve on said plate having a concave outer end shaped to conform with the curvature of an eyeball; a

pin slidable in said sleeveand having its inner end engaging said arm; the outer end of the-pin normally projecting into said concave end of the sleeve; means for adjusting the balance of the pointer when the plate is held in operative position; a bushing slidable on said sleeve; handles carried by said bushing whereby the tonometer. may be supported and the bushing may be shifted towards the concave end of the sleeve; and means for controlling the force applied to the bushingin,

shifting the same during measurement.

7. In a tonometer as set forth in claim 6, said oted at the end of the key adjacent the concave end of the sleeve; means gravitationally maintaining the lever at an acute angle to the sleeve when the plate is in operative position; an adjustable Weight on said lever; and said lever having an indicia thereon cooperating with the adjacent end of the bushing to denote the proper position of the bushing on the sleeve during its movement towards the concave end of the sleeve when the reading of the pointer on the scal should be taken.

9. In a tonometer as set forth in claim 6, said controlling means comprising a key on said sleeve engaging a key way in said bushing, a lever piv-" oted at the end of the key adjacent the concave end of the sleeve; means gravitationally maintaining the lever at anacute angle to the. sleeve when the plate is in operative position; an ad-.

justable weight on said lever having arecess in its periphery conforming with, the shape of the sleeve to permit the lever to swing towards the sleeve when the bushing slidably contacts the lever; and said lever having an indici a thereon cooperating with the adjacent end of the bushing 'to denote the proper position of the bushing on the sleeve during its movement towards the concave end of the sleeve when the reading of the pointer on the scale should be taken.

10. A tonorneter, comprising a plate having a scale; a, pointer pivotally mounted thereon and swingable over said scale; an arm extending laterallyof said pointer; a sleeve having a bore 01T- set from said pivot; a pin slidably mounted in said bore and having a head engaging said arm;

the outer end of the sleevehaving an enlargement coaxial with said bore provided with a concave outer faceshaped to conform with the curvature'of an eyeball; the outer end of the pin nor mally projecting into said concavity; means for adjusting the balance of the pointer when the plate is held in operative position; a bushing slidably mounted on said sleeve; handles carried by said bushing whereby the tonometer may be supported and the bushingmay be shifted towards the enlargement of the sleeve; and means for controlling the force applied to the bushing in shifting the same during measurement.

11. In a tonometer as set forth in claim 10, said adjusting; means comprising a lever on the said .a shiftable weight on said lever.

v12. In a tonometer as set forth in claim 10, said arm inclined in the direction of the pointer; and v of the bushing to denote the proper position of the bushing on the sleeve during its movement towards the enlargement when the reading of the pointer on the scale' should be taken.

13. In a tonometer as set forth in claim 10, said controlling mean comprising a key carried by said sleeve engaging a keyway in said bushing, a lever pivoted at the end of the key adjacent the enlargement; means normally maintaining the lever at an acute angle to the sleeve when the plate is in operative position; an adjustable weight on said lever having a recess in. its periphery conforming with the shape of the sleeve to permit the lever to swing towards the sleeve when the bushing slidably contacts the lever; and said lever having an indicia thereon cooperating with the adjacent end of the bushing to denote the proper position of the bushing on the sleeve during its movement towards the enlargement when the reading. of the pointer should be taken.

ULRICH 

